JP6973168B2 - Vehicle power transmission device - Google Patents

Description

The present invention relates to a vehicle power transmission device.

According to Patent Document 1, in a vehicle power transmission device, when a shift operation is performed in a non-forward range, the electric oil pump is started, and the mechanical oil pump is caused by a decrease in the engine rotation speed accompanying the subsequent engine stop operation. It is disclosed that a hydraulic oil is supplied to the meshing clutch by an electric oil pump so that the actuator stroke is held at the engaging position of the synchro mechanism even if the supply hydraulic pressure from the engine is reduced.

Japanese Unexamined Patent Publication No. 2016-050617

When the shift operation is performed to the N range, which is the non-forward range, while the idling stop is performed in the D range, which is the forward range, the oil pressure accumulated in the accumulator between the oil pump and the forward clutch is released. After that, when the accumulator is re-shifted from the N range to the D range, the accumulator is re-accumulated, but when the engine is stopped, the oil is not supplied from the mechanical oil pump, so the line is only the oil from the electric oil pump. The pressure drops and the synchronization mechanism is released. When the engine is started in this state, the line pressure is restored from the low pressure state by the hydraulic pressure from the mechanical oil pump, so that the synchro mechanism is re-engaged and then the forward clutch is engaged. Therefore, when the D → N → D shift operation is performed by the shift operation during the idling stop, if the forward clutch is engaged to start the vehicle, hesitation may occur.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power transmission device for a vehicle capable of realizing a smooth start.

In order to solve the above-mentioned problems and achieve the object, the vehicle power transmission device according to the present invention has a stepped speed change mechanism having a gear stage, a first clutch, and a synchro mechanism to transmit power. A 1 power transmission path and a second power transmission path for transmitting power via a belt-type stepless transmission and a second clutch are provided in parallel, and the stepped transmission mechanism, the stepless transmission, and the like. A mechanical oil pump and an electric oil pump for supplying hydraulic oil to the first clutch and the second clutch are provided, and a plurality of shift ranges including a forward range and a non-forward range shift. In a vehicle power transmission device that can be selectively switched by operation, the shift range is switched from the forward range to the non-forward range during idling stop, and then from the non-forward range to the forward range. When it is determined that there is a possibility of hesitation, the power is transmitted by the second power transmission path.

The vehicle power transmission device according to the present invention selects power transmission by belt drive via the second power transmission path when it is determined that there is a possibility of hesitation, so that a smooth start can be realized. It has the effect of being able to do it.

FIG. 1 is a skeleton diagram illustrating a configuration of a vehicle drive device according to an embodiment. FIG. 2 is a flowchart showing an example of clutch engagement target calculation control at the time of D → N → D shift operation from idling stop in the D range by executing S & S control. FIG. 3 is a flowchart showing another example of clutch engagement target calculation control at the time of D → N → D shift operation from idling stop in the D range by performing S & S control. FIG. 4 is a time chart at the time of selecting the clutch for belt traveling at the time of D → N → D shift operation from idling stop in the D range by performing S & S control. FIG. 5 is a time chart at the time of selecting the forward clutch at the time of D → N → D shift operation from idling stop in the D range by performing S & S control.

Hereinafter, an embodiment of the vehicle power transmission device according to the present invention will be described. The present invention is not limited to the present embodiment.

FIG. 1 is a skeleton diagram of a vehicle drive device 8 provided with a vehicle power transmission device 12 according to an embodiment. The vehicle drive device 8 includes an engine 10 used as a drive force source for traveling and a vehicle power transmission device 12. The engine 10 is an internal combustion engine such as a gasoline engine or a diesel engine. The vehicle power transmission device 12 includes a torque converter 14 as a fluid transmission device, an automatic transmission 16, and a differential gear device 18, and the output of the engine 10 is output from the torque converter 14 via the automatic transmission 16. Is transmitted to the differential gear device 18 and distributed to the left and right drive wheels 20L and 20R. The torque converter 14 includes a pump impeller 14p connected to the crank shaft of the engine 10 and a turbine impeller 14t connected to the input shaft 22 of the automatic transmission 16 to transmit power via fluid. At the same time, it is directly connected via the lockup clutch 15. A mechanical oil pump 74 is provided on the pump impeller 14p, and is used as a hydraulic source for the hydraulic control circuit 70 shown by the broken line in FIG. 1 by being rotationally driven by the engine 10 to output hydraulic pressure.

The automatic transmission 16 is connected to an input shaft 22 integrally provided with a turbine shaft which is an output rotating member of the torque converter 14, a belt-type stepless transmission 24 connected to the input shaft 22, and also to the input shaft 22. A common output rotation member of the forward / backward switching device 26 provided in parallel with the stepless transmission 24, the gear transmission mechanism 28 which is a stepped transmission mechanism having a gear stage, the stepless transmission 24, and the gear transmission mechanism 28. The output shaft 30 and the reduction gear device 32 are provided. The small diameter gear 34 of the reduction gear device 32 is meshed with the ring gear 36 of the differential gear device 18. The forward / backward switching device 26 and the gear shifting mechanism 28 correspond to a gear transmission mechanism. In the automatic transmission 16 configured in this way, the output of the engine 10 is transmitted from the torque converter 14 to the output shaft 30 via the continuously variable transmission 24, or front and rear without going through the continuously variable transmission 24. It is transmitted to the output shaft 30 via the advance switching device 26 and the gear transmission mechanism 28, and further transmitted to the left and right drive wheels 20L and 20R via the reduction gear device 32 and the differential gear device 18.

As described above, the automatic transmission 16 of the present embodiment includes a first power transmission path TP1 that transmits the output of the engine 10 from the input shaft 22 to the output shaft 30 via the forward / backward switching device 26 and the gear transmission mechanism 28. A second power transmission path TP2 that transmits the output of the engine 10 from the input shaft 22 to the output shaft 30 via the stepless transmission 24 is provided, and the first power transmission path TP1 is provided according to the traveling state of the vehicle. The second power transmission path TP2 is switched. Therefore, the automatic transmission 16 transmits the power transmission in the forward clutch C1 and the second power transmission path TP2, which are the first clutches as the first connection / disconnection device for connecting / disconnecting the power transmission in the first power transmission path TP1. A belt traveling clutch C2, which is a second clutch as a second disconnection / disconnection device, is provided. In the first power transmission path TP1, a hydraulic meshing type dog clutch Cd, which is a meshing type transmission device, is further in series with the forward clutch C1 and the gear transmission mechanism 28 and downstream of them. It is provided.

The forward / backward switching device 26 is mainly composed of a double pinion type planetary gear device, the sun gear 26s is integrally connected to the input shaft 22, and the carrier 26c can rotate relative to the input shaft 22 coaxially. It is connected to the arranged small diameter gear 42. On the other hand, the ring gear 26r is selectively connected to the case 40 via the reverse brake B1 to stop rotation, and the input shaft 22 and the carrier 26c are selectively connected via the forward clutch C1. It has become. Then, when the forward clutch C1 is engaged and the reverse brake B1 is released, the input shaft 22 is directly connected to the small diameter gear 42, and the forward power transmission state is established. Further, when the reverse brake B1 is engaged and the forward clutch C1 is released, the small diameter gear 42 is rotated in the opposite direction to the input shaft 22, and the reverse power transmission state is established. Further, when both the forward clutch C1 and the reverse brake B1 are released, the power transmission is cut off in the neutral state.

The forward clutch C1 and the reverse brake B1 are both multi-plate type friction engagement devices in which a plurality of friction materials are frictionally engaged by a hydraulic cylinder, and the C1 hydraulic PC1 and the B1 hydraulic PB1 supplied to the hydraulic cylinder are provided. By controlling the pressure adjustment by the hydraulic operation control unit 72, the engaging force, that is, the transmission torque capacity of the forward clutch C1 and the reverse brake B1 is continuously adjusted.

The gear shifting mechanism 28 includes a small-diameter gear 42, a large-diameter gear 46 that is provided on the counter shaft 44 so as to be non-rotatable and meshes with the small-diameter gear 42, and a small-diameter idler gear that is coaxially and relatively rotatable with respect to the counter shaft 44. It has 48. A dog clutch Cd is provided between the counter shaft 44 and the idler gear 48, and the power transmission between them is disconnected and connected. The dog clutch Cd is provided with a synchro mechanism such as a synchronizer ring, and when the clutch hub sleeve 50 is moved in the connection direction by the hydraulic actuator 52, the idler gear 48 is rotated synchronously with the counter shaft 44 via the synchro mechanism. When the clutch hub sleeve 50 is further moved, the idler gear 48 is connected to the counter shaft 44 via the spline teeth provided on the inner peripheral surface of the clutch hub sleeve 50. The hydraulic actuator 52 is a hydraulic cylinder, and the hydraulic pressure (line hydraulic PL) supplied to the hydraulic actuator 52 maintains the connected state of the idler gear 48 and the counter shaft 44 against the urging force of the return spring.

The idler gear 48 meshes with a large-diameter gear 58 provided on the output shaft 30, and one of the forward clutch C1 and the reverse brake B1 is engaged, and the dog clutch Cd is connected to the engine. The first power transmission path TP1 in which the output of 10 is sequentially transmitted from the input shaft 22 to the output shaft 30 via the forward / backward switching device 26, the gear transmission mechanism 28, the idler gear 48, and the large diameter gear 58 is established. .. That is, it is possible to travel in the gear drive mode in which power is transmitted via the first power transmission path TP1. It should be noted that shifting (deceleration) is also performed between the small-diameter idler gear 48 and the large-diameter gear 58, and it can be considered that the gear shifting mechanism 28 includes the idler gear 48 and the large-diameter gear 58.

The continuously variable transmission 24 is wound around a primary pulley 60 provided on the input shaft 22, a secondary pulley 64 provided on a pulley rotating shaft 62 coaxial with the output shaft 30, and a primary pulley 60 and a secondary pulley 64. The transmission belt 66 is provided, and power transmission is performed via friction between the primary pulley 60 and the secondary pulley 64 and the transmission belt 66. The primary pulley 60 and the secondary pulley 64 are provided with hydraulic cylinders 60c and 64c as hydraulic actuators that apply thrust to change the V-groove width, respectively. Then, for example, the primary hydraulic Ppri supplied to the hydraulic cylinder 60c is controlled by the hydraulic operation control unit 72 of the hydraulic control circuit 70, so that the V-groove widths of the primary pulley 60 and the secondary pulley 64 change, and the transmission belt The hanging diameter (effective diameter) of 66 is changed, and the gear ratio γ2 is continuously changed. Further, the secondary hydraulic pressure Psec supplied to the hydraulic cylinder 64c is pressure-adjusted and controlled by the hydraulic operation control unit 72, so that the belt pinching pressure is adjusted so that the transmission belt 66 does not slip.

Here, the gear ratio γ1 of the first power transmission path TP1 determined by the gear ratio of the gear transmission mechanism 28 or the like is larger than the maximum value γ2max of the gear ratio γ2 of the second power transmission path TP2, and is, for example, when the vehicle starts or is high. The first power transmission path TP1 is used during load traveling, and is switched to the second power transmission path TP2 as the vehicle speed V increases or the required driving force decreases. The gear ratio γ1 and the gear ratio γ2 are ratios (Nt / No) of the turbine rotation speed Nt to the output rotation speed No, which is the rotation speed of the output shaft 30. The turbine rotation speed Nt coincides with the input rotation speed, which is the rotation speed of the input shaft 22.

The output shaft 30 is arranged so as to be coaxially and relative to the pulley rotation shaft 62 so as to be rotatable relative to the pulley rotation shaft 62. Power transmission to and from the secondary pulley 64 is disconnected. When the belt traveling clutch C2 is engaged, the output of the engine 10 is transmitted from the input shaft 22 to the output shaft 30 via the continuously variable transmission 24, and the second power transmission path TP2 is established. That is, it is possible to travel in the belt drive mode in which power transmission is performed via the second power transmission path TP2. The belt traveling clutch C2 provided on the output side of the stepless transmission 24 is a multi-plate type friction engaging device in which a plurality of friction materials are frictionally engaged by a hydraulic cylinder, and is supplied to the hydraulic cylinder C2. By controlling the pressure of the hydraulic PC 2 by the hydraulic operation control unit 72, the engaging force, that is, the transmission torque capacity is continuously adjusted.

The hydraulic control circuit 70 includes an electric oil pump 76 in addition to the mechanical oil pump 74. The mechanical oil pump 74 and the electric oil pump 76 supply hydraulic oil to the gear transmission mechanism 28, the continuously variable transmission 24, the forward clutch C1, the belt traveling clutch C2, and the like. The electric oil pump 76 outputs a predetermined oil pressure by being rotationally driven by an electric motor 78 for a pump at an arbitrary drive torque at an arbitrary time. Further, the hydraulic control circuit 70 includes an accumulator between the electric oil pump 76 and the mechanical oil pump 74 and the forward clutch C1. The electric motor 78 for the pump is controlled by the ECU 80, and the lockup clutch 15 is released and the engine 10 is released from the power transmission path, for example, when the accelerator is coasted, the brake is operated for deceleration, or the vehicle is stopped. Is disconnected and the engine 10 is stopped by a fuel cut or the like. The mechanical oil pump 74 is operated when sufficient oil pressure cannot be obtained, and a predetermined oil pressure is output from the electric oil pump 76. do. The maximum output oil pressure of the electric oil pump 76 is much lower than that of the mechanical oil pump 74, and only the minimum necessary oil pressure is output.

The hydraulic operation control unit 72 is a valve body provided with an electromagnetic switching valve for switching oil passages, an electromagnetic hydraulic control valve for controlling hydraulic pressure, and the like, and the switching valve and the hydraulic control valve are electrically controlled by the ECU 80. .. As a result, the primary oil pressure Ppri, the secondary oil pressure Psec, the C1 oil pressure PC1, the C2 oil pressure PC2, and the B1 oil pressure PB1 are pressure-controlled, and the lockup clutch 15 is controlled to engage and disengage. Further, the dog clutch Cd is connected or disconnected by moving the clutch hub sleeve 50 in the axial direction via the hydraulic actuator 52.

The ECU (electronic control unit) 80 performs output control of the engine 10, shift control of the continuously variable transmission 24, switching control of the first power transmission path TP1 and the second power transmission path TP2, and the like. The ECU 80 includes a so-called microprocessor having a CPU, a ROM, a RAM, an input / output interface, and the like. The ECU 80 performs signal processing according to a program stored in advance in the ROM while using the temporary storage function of the RAM. The ECU 80 has various types such as an engine rotation speed Ne, a turbine rotation speed Nt, an output rotation speed No, an accelerator operation amount Acc which is an operation amount of the attacker peggle, and a brake operation signal Br which is a signal indicating a brake operation (depressing operation). Various information necessary for the control of the above is supplied.

Further, when the user operates the shift lever, the ECU 80 has a forward range such as a D (drive) range and a non-forward range such as an N (neutral) range, a P (parking) range, and an R (reverse) range. And, multiple shift ranges including, are switched to the shift range according to the position of the shift lever.

The ECU 80 can perform S & S (stop and start) control. In S & S control, the lockup clutch 15 is released when the brake is decelerated when the brake is depressed during forward driving to disconnect the engine 10 from the power transmission path and stop the fuel supply to the engine 10 (fuel). (Cut) to stop the rotation of the engine 10 (stop idling). Whether or not the brake is ON can be determined by the presence or absence of the brake operation signal Br. Then, when a predetermined release condition such as the release of the brake operation is satisfied, the fuel supply to the engine 10 is immediately restarted, the engine 10 is restarted, and the normal operation is resumed.

FIG. 2 is a flowchart showing an example of clutch engagement target calculation control at the time of D → N → D shift operation from idling stop in the D range by performing S & S control.

First, the ECU 80 determines whether the idling stop is in the D range (step S1). When it is determined that the idling stop is not in the D range (No in step S1), the ECU 80 repeatedly executes the process of step S1 until it is determined that the idling stop is in the D range. On the other hand, when it is determined that the idling stop is in progress in the D range (Yes in step S1), the ECU 80 determines whether the shift operation has been performed from the D range to the N range (P range, R range) (step S2).

When it is determined that the shift operation from the D range to the N range (P range, R range) has not been performed (No in step S2), the ECU 80 shifts from the D range to the N range (P range, R range). The process of step S2 is repeatedly executed until it is determined that the process has been performed. On the other hand, when it is determined that the shift operation has been performed from the D range to the N range (P range, R range) (Yes in step S2), the ECU 80 returns from the S & S control and the shift operation is performed again to the D range. It is determined whether or not (step S3).

If it is determined that the reshift operation to the D range has not been performed (No in step S3), the ECU 80 repeatedly executes the process of step S3 until the reshift operation is performed to the D range. On the other hand, when it is determined that the reshift operation has been performed to the D range (Yes in step S3), the ECU 80 determines whether there is a possibility that the synchronization mechanism may be off due to accumulator filling (step S4).

When it is determined that the synchro mechanism may be disengaged due to accumulator filling (Yes in step S4), the ECU 80 sets the clutch engagement target as the belt traveling clutch C2 (step S5), and ends a series of controls. As a result, when it is determined that the synchronization mechanism may be disengaged due to accumulator filling, in other words, there is a possibility of hesitation, the ECU 80 engages the belt traveling clutch C2 to engage the second power transmission path TP2. Since the power transmission by the belt drive mode via the vehicle is selected, a smoother start can be realized.

On the other hand, when it is determined that there is no possibility that the synchro mechanism is disengaged due to accumulator filling (No in step S4), the ECU 80 sets the clutch engagement target as the forward clutch C1 (step S6) and ends a series of controls. As a result, when it is determined that there is no possibility of the synchronization mechanism coming off due to accumulator filling, in other words, there is no possibility of hesitation, the ECU 80 engages the forward clutch C1 and goes through the first power transmission path TP1. The vehicle can be started by power transmission in the gear drive mode.

Next, the clutch in the case of determining whether or not there is a possibility of hesitation depending on whether or not a predetermined time has elapsed from the D → N shift operation and the engine speed Ne is equal to or less than the predetermined value during the N → D shift operation. The engagement target calculation control will be described.

FIG. 3 is a flowchart showing another example of clutch engagement target calculation control at the time of D → N → D shift operation from idling stop in the D range by performing S & S control. FIG. 4 is a time chart when the belt traveling clutch C2 is selected during the D → N → D shift operation from the idling stop in the D range by performing the S & S control. FIG. 5 is a time chart when the forward clutch C1 is selected at the time of D → N → D shift operation from idling stop in the D range by performing S & S control.

First, as shown in FIG. 3, the ECU 80 determines whether the idling stop is in the D range (step S11). When it is determined that the idling stop is not in the D range (No in step S11), the ECU 80 repeatedly executes the process of step S11 until it is determined that the idling stop is in the D range. On the other hand, when it is determined that idling stop is in progress in the D range (Yes in step S11), the ECU 80 determines whether the shift operation has been performed from the D range to the N range (P range, R range) (step S12). ..

When it is determined that the shift operation from the D range to the N range (P range, R range) has not been performed (No in step S12), the ECU 80 shifts from the D range to the N range (P range, R range). The process of step S12 is repeatedly executed until it is determined that the process has been performed. On the other hand, when it is determined that the shift operation has been performed from the D range to the N range (P range, R range) (Yes in step S12, time t1 in FIG. 4, time t11 in FIG. 5), the ECU 80 returns from S & S control. At the same time, it is determined whether the reshift operation has been performed to the D range (step S13).

If it is determined that the reshift operation to the D range has not been performed (No in step S13), the ECU 80 repeatedly executes the process of step S13 until the reshift operation to the D range is performed. On the other hand, when it is determined that the reshift operation has been performed to the D range (Yes in step S13), the ECU 80 has been after the shift operation has been performed from the D range to the N range (P range, R range). ) It is determined whether the predetermined time or more has passed (step S14). The time t2 in FIG. 4 and the time t12 in FIG. 5 are the timings at which the clutch C1 indicated pressure at the time of release is reached. The predetermined time in FIG. 4 is t2-t1, and the predetermined time in FIG. 5 is t12-t11.

When it is determined that a predetermined time or more has not elapsed from the deviation of the D range (No in step S14), the ECU 80 sets the engagement target of the clutch as the forward clutch C1 (step S17), and ends a series of control. Then, the ECU 80 increases the clutch C1 instruction pressure so that the forward clutch C1 changes from the released state to the engaged state (time t14 in FIG. 5), engages the forward clutch C1, and causes the first power transmission path. The vehicle is started by power transmission in the gear drive mode via TP1. On the other hand, when it is determined that a predetermined time or more has elapsed from the deviation from the D range (Yes in step S14), the ECU 80 determines whether the engine speed Ne is equal to or less than the predetermined value at the time of the reshift operation to the D range (step S15). ).

When it is determined that the engine speed Ne is equal to or less than a predetermined value during the reshift operation to the D range (Yes in step S15, time t3 in FIG. 4), the ECU 80 sets the clutch engagement target as the belt traveling clutch C2. (Step S16), a series of controls is terminated. When it is determined that there is a possibility of hesitation, the ECU 80 increases the clutch C2 instruction pressure so that the belt traveling clutch C2 changes from the released state to the engaged state (time t4 in FIG. 4), and the belt. The traveling clutch C2 is engaged to select power transmission in the belt drive mode via the second power transmission path TP2. Therefore, a smoother start can be realized.

On the other hand, when it is determined that the engine speed Ne is not equal to or less than a predetermined value during the reshift operation to the D range (No in step S15, time t13 in FIG. 5), the ECU 80 sets the clutch engagement target to the forward clutch C1. (Step S17), a series of control is terminated. Then, the ECU 80 increases the clutch C1 instruction pressure so that the forward clutch C1 changes from the released state to the engaged state (time t14 in FIG. 5), engages the forward clutch C1, and causes the first power transmission path. The vehicle is started by power transmission in the gear drive mode via TP1.

8 Vehicle drive 10 Engine 12 Vehicle power transmission 70 Hydraulic control circuit 74 Mechanical oil pump 76 Electric oil pump 80 ECU
C1 Forward clutch C2 Belt running clutch TP1 1st power transmission path TP2 2nd power transmission path

Claims (1)

Stepwise variable transmission mechanism having a gear, the first clutch, and the through the first power transmission path for transmitting the power of the engine via the synchronizing mechanism, and a continuously variable transmission and a second clutch of the belt-type engine The second power transmission path for transmitting the power of the above is provided in parallel, and the gear ratio of the first power transmission path is made larger than the maximum value of the gear ratio of the second power transmission path.
A mechanical oil pump and an electric oil pump for supplying hydraulic oil to the stepped speed change mechanism, the continuously variable transmission, the first clutch, and the second clutch are provided, and the mechanical oil is provided. The pump is rotationally driven by the engine.
In a vehicle power transmission device in which a plurality of shift ranges including a forward range and a non-forward range can be selectively switched by a shift operation.
When the vehicle starts, power is transmitted by the first power transmission path, while the shift range is switched from the forward range to the non-forward range during idling stop, and then switched from the non-forward range to the forward range. Whether or not a predetermined time has elapsed from the shift operation from the forward range to the non-forward range and the engine rotation speed at the time of the shift operation from the non-forward range to the forward range is equal to or less than a predetermined value. A power transmission device for a vehicle, characterized in that power is transmitted by the second power transmission path when it is determined that there is a possibility of hesitation.

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